And here is the compiler error:
In file included from RCXIR_Test.ino:1:
C:\Users\Family\Dropbox\Matt's Technology\Arduino\Sketch Book\libraries\RCXIR/RCXIR.h:30: error: 'FIFOClass' does not name a type
I guess it's most likely that the FIFO library isn't getting linked to the RCXIR library.